First, we need to find the total number of ways Sandra can select two bills from the envelope without returning the first bill. This can be calculated using combinations:
Total ways to select 2 bills = (5 + 10 + 15) choose 2 = 30 choose 2 = 435
Next, we need to find the number of ways Sandra can select a $10 bill and a $50 bill.
Number of ways to select a $10 bill = 5
Number of ways to select a $50 bill = 15
Therefore, number of ways to select a $10 bill and a $50 bill = 5 * 15 = 75
Finally, we can calculate the probability of getting a $10 bill and a $50 bill by dividing the number of ways to select a $10 bill and a $50 bill by the total ways to select 2 bills:
Probability = Number of ways to select a $10 bill and a $50 bill / Total ways to select 2 bills
Probability = 75 / 435
Probability = 5 / 29
Therefore, the probability of getting a $10 bill and a $50 bill is 5 / 29 or approximately 0.1724.
a money envelope contains five 10 dollar bills and ten $20 bills and fifteen $50 bills. Sandra randomly selects two bills without returning the first bill. What is the probabillity of getting a $10 bill and a $50 bill. Write your answer in the simplest form
1 answer
1 answer